Abstract: A hard disk drive includes multiple actuator assemblies, each of which includes a head-stack assembly (HSA) including an end-arm to which a single head-gimbal assembly (HGA) is coupled, where this end-arm is configured with a notch along one side and a triangular or quadrilateral-shaped through-hole at a root-side of the end-arm, and where the HSA further includes a plurality of other end- and inner-arms to each of which two HGAs are coupled and none of which have a through-hole near their root. The single-HGA end-arm may be further configured with an outer damper having a through-hole coincident with the end-arm through-hole, such that the through-hole of the end-arm is not covered by this damper, and an inner damper having no through-hole, such that the through-hole of the end-arm is covered by this damper. Gains are thereby better matched across all HGAs for problematic arm and system modes.

Abstract: A hard disk drive includes multiple actuator assemblies, each of which includes a head-stack assembly (HSA) including an end-arm to which a single head-gimbal assembly (HGA) is coupled, where this end-arm is configured with a notch along one side and a triangular or quadrilateral-shaped through-hole at a root-side of the end-arm, and where the HSA further includes a plurality of other end- and inner-arms to each of which two HGAs are coupled and none of which have a through-hole near their root. The single-HGA end-arm may be further configured with an outer damper having a through-hole coincident with the end-arm through-hole, such that the through-hole of the end-arm is not covered by this damper, and an inner damper having no through-hole, such that the through-hole of the end-arm is covered by this damper. Gains are thereby better matched across all HGAs for problematic arm and system modes.

Abstract: Control circuitry is disclosed configured to control inner fine actuators of a first plurality of inner actuator arms and independently control a first outer fine actuator of a first outer actuator arm. Inner fine actuators of a second plurality of inner actuator arms are controlled while independently controlling a second outer fine actuator of a second outer actuator arm. Each actuator arm comprises at least one head configured to access a disk surface of a disk.

Abstract: A data storage device is disclosed comprising a plurality of disks each comprising a top disk surface and a bottom disk surface, and a plurality of actuator arms each comprising a first fine actuator configured to actuate a top head over one of the top disk surfaces and a second fine actuator configured to actuate a bottom head over one of the bottom disk surfaces. A first fine driver controls the fine actuators of an even interleave of the actuator arms, and a second fine driver controls the fine actuators of an odd interleave of the actuator arms.

Abstract: Control circuitry is disclosed configured to control inner fine actuators of a first plurality of inner actuator arms and independently control a first outer fine actuator of a first outer actuator arm. Inner fine actuators of a second plurality of inner actuator arms are controlled while independently controlling a second outer fine actuator of a second outer actuator arm. Each actuator arm comprises at least one head configured to access a disk surface of a disk.

Abstract: A hard disk drive includes multiple actuator assemblies, each of which includes a head-stack assembly (HSA) including an end-arm to which a single head-gimbal assembly (HGA) is coupled, where this end-arm is configured with a notch along one side and a triangular or quadrilateral-shaped through-hole at a root-side of the end-arm, and where the HSA further includes a plurality of other end- and inner-arms to each of which two HGAs are coupled and none of which have a through-hole near their root. The single-HGA end-arm may be further configured with an outer damper having a through-hole coincident with the end-arm through-hole, such that the through-hole of the end-arm is not covered by this damper, and an inner damper having no through-hole, such that the through-hole of the end-arm is covered by this damper. Gains are thereby better matched across all HGAs for problematic arm and system modes.

Abstract: A data storage device is disclosed comprising a plurality of disks each comprising a top disk surface and a bottom disk surface, and a plurality of actuator arms each comprising a first fine actuator configured to actuate a top head over one of the top disk surfaces and a second fine actuator configured to actuate a bottom head over one of the bottom disk surfaces. A first fine driver controls the fine actuators of an even interleave of the actuator arms, and a second fine driver controls the fine actuators of an odd interleave of the actuator arms.

Abstract: A unitary enclosure base for a data storage device integrally includes a first surface beneath a bottom disk, a bypass channel formed with an entry area with a lower surface below the first surface, a second surface lower than the first surface and beneath an actuator arm that services the bottom surface of the bottom disk, and a flow diverter extending upward from the first surface and positioned upstream of the actuator arm. The diverter may be positioned relative to the bypass channel such that disk-generated gas flow is diverted into the bypass channel away from the actuator arm. The base may further include a spoiler extending upward from the first surface and positioned downstream of the actuator arm. The spoiler may be positioned to inhibit a wake effect upon the actuator arm.

Abstract: A hard disk drive enclosure with conductive paths. A base plate comprising an electrically conductive material with at least one contact surface that allows for an electrically conductive path, wherein the at least one contact surface has a substantially flat surface. A cover comprising an electrically conductive material comprising at least one tab with a substantially flat surface for contacting the at least one contact surface of the base plate, wherein the at least one tab contacts the at least one contact surface of the base plate with a force and forms an electrically conductive path between the cover and the based plate, and wherein the at least one tab deforms upon the contact with the at least one contact surface of the base plate with the force.

Abstract: A method of fabricating a photomask used to form a lens. The method includes the steps of generating mask pattern data for each of a plurality of grid cells constituting a mask pattern for the lens, and fabricating the photomask based on the mask pattern data. The step of generating the mask pattern data includes acquiring data which represents a transmitted light distribution required for the photomask to fabricate the lens, in which the transmitted light distribution includes a quantity of transmitted light in each of the plurality of grid cells, and determining whether to place a shield on each of the plurality of grid cells by binarizing the quantity of transmitted light in each of the plurality of grid cells in order of increasing or decreasing distance from a center of the mask pattern using an error diffusion method.

Abstract: Approaches for a fluid dynamic bearing (FDB) system for use within a hard-disk drive. A fluid dynamic bearing (FDB) system may comprise an upper conical bearing and a lower conical bearing that are both disposed along a stationary shaft on which a magnetic-recording disk is rotatably mounted. The upper conical bearing and the lower conical bearing may have different cone angles, diameters, and/or lubricants to produce a desired difference in stiffness between the first conical bearing and the second conical bearing. By adjusting characteristics of the fluid dynamic bearing (FDB) system to achieve the desired bearing stiffness ratio, the tendency for the magnetic-recording disks to experience a sustained vibration when the hard-disk drive receives a mechanical shock is reduced. By preventing the magnetic-recording disks from sustained vibration after a mechanical shock, data may be written to and read from the magnetic-recording disks with greater reliability.

Abstract: Embodiments of the present invention help to achieve a solder joining structure having high reliability, in which even if a componential material of a flange of a feed-through of a sealed magnetic disk drive is an iron-based material such as Kovar™, and a componential material of a base of the drive is an aluminum-based alloy, leakage of low-density gas is dramatically reduced. According to one embodiment, a base has a stepped portion in the inside of a periphery of an opening, and an inclined surface extending to the outside of the base is formed at an edge of a surface of the stepped portion, on which a flange of a feed-through is placed, thereby when the stepped portion of the base is joined by soldering with the flange of the feed-through, a solder fillet is formed not only in the inside of the base, but also in the outside thereof.

Abstract: Approaches for a fluid dynamic bearing (FDB) system for use within a hard-disk drive. A fluid dynamic bearing (FDB) system may comprise an upper conical bearing and a lower conical bearing that are both disposed along a stationary shaft on which a magnetic-recording disk is rotatably mounted. The upper conical bearing and the lower conical bearing may have different cone angles, diameters, and/or lubricants to produce a desired difference in stiffness between the first conical bearing and the second conical bearing. By adjusting characteristics of the fluid dynamic bearing (FDB) system to achieve the desired bearing stiffness ratio, the tendency for the magnetic-recording disks to experience a sustained vibration when the hard-disk drive receives a mechanical shock is reduced. By preventing the magnetic-recording disks from sustained vibration after a mechanical shock, data may be written to and read from the magnetic-recording disks with greater reliability.

Abstract: Components and assemblies for a hard disk drive (HDD) with a recessed actuator joint are described. A rotary actuator hub assembly comprises a shaft having a flange, and a pivot seat on which the flange is seated when the shaft is fastened to an HDD chassis. According to an embodiment, the pivot seat has at least one “contact-reducing feature” recessed from the surface of the pivot seat at which the seat contacts the flange. A purpose of the contact-reducing feature(s) of the pivot seat is to weaken the joint between the actuator hub assembly and the chassis, thereby mechanically loosening the rotary actuator assembly from the chassis. Consequently, movements to and vibrations from the chassis are less likely to be transmitted to the rotary actuator assembly and, ultimately, to the HDD read/write head(s).

Abstract: A sealing type magnetic disc drive comprising a disc, a spindle motor for rotationally driving the disc, a head for recording or reproducing information on the disc, a base on which an actuator assembly is provided to move the head in the radius direction on the disc, and a cover jointed with the base, and low density gas is filled in the space where the base and the cover are joined, wherein low vapor pressure oil or a low viscosity adhesive is filled in a hole present at the joint of the base and the cover.

Abstract: A method of fabricating a photomask used to form a lens. The method includes the steps of generating mask pattern data for each of a plurality of grid cells constituting a mask pattern for the lens, and fabricating the photomask based on the mask pattern data. The step of generating the mask pattern data includes acquiring data which represents a transmitted light distribution required for the photomask to fabricate the lens, in which the transmitted light distribution includes a quantity of transmitted light in each of the plurality of grid cells, and determining whether to place a shield on each of the plurality of grid cells by binarizing the quantity of transmitted light in each of the plurality of grid cells in order of increasing or decreasing distance from a center of the mask pattern using an error diffusion method.

Abstract: A method of generating mask pattern data of a photomask used to form microlenses divides a pattern formation surface of a mask pattern to be used for the photomask into a plurality of grid cells, acquires data that represent a transmitted light distribution of the mask pattern to be used for the photomask, determines whether to place a shield on each of the plurality of grid cells by binarizing the plurality of grid cells in order of increasing or decreasing distance from a center of the pattern formation surface using an error diffusion method, to acquire the transmitted light distribution, and generates mask pattern data that represent an arrangement of the shields, based on the determination.

Abstract: Embodiments of the present invention provide a magnetic disk drive that can estimate the amount of gas filled in a housing precisely and simply. According to one embodiment, a magnetic disk drive including a housing in which a magnetic disk and a magnetic head are accommodated and gas having lower density than air is filled, a heating body provided in the housing, and means for holding a reference value of a parameter representing the temperature change speed of the heating body when the heating body is heated in the housing filled with a predetermined reference amount of the gas.

Abstract: Embodiments in accordance with the present invention improve bonding reliability in a feedthrough sealing portion. According to one embodiment of the present invention, an opening of a through hole is provided on the bottom of the base of the magnetic disk device and a feedthrough mounting plane which is one of the steps formed toward the outside of the device is provided around the opening. The feedthrough includes a flange and pins which are fixed to the flange by a glass material and pass an electric signal. The flange is larger in outer shape than the opening of the base. The periphery of the flange of the feedthrough is mounted on the feedthrough mounting plane of the base from the outside and bonded thereto by solder.

Abstract: In a disk drive device in which low-density gas is sealed, embodiments of the present invention help to improve joint reliability at a solder joint section between a feedthrough and an enclosure with respect to stress applied by deformation due to changes in temperature environment in use. According to one embodiment, helium gas is sealed in an interior space of an HDD. A feedthrough is solder jointed to a feedthrough mounting surface of a base. At a part with relatively large thermal stress, a width of the feedthrough mounting surface is increased, and at a part with relatively small thermal stress, a width of the feedthrough mounting surface is decreased. This prevents a crack penetrating path from being generated at the solder joint section due to the thermal stress and prevents the solder joint section from contacting pins.